I have a Baby Lock Crown Jewel which is the same machine as the HQ Avante. I have a Baby Lock dealer within driving distance so that was part of my decision (an important part) although I have not yet needed the dealer. I went to a quilt show and tried all the machines there (which were most of the 18 inch or larger ones).
I loved the feel of the Crown Jewel with a Grace Majestic frame (10 feet - 120 inches). I have done several large queen quilts on it and could probably do a small king but not a large king. 10 feet was all I had room for as you have to be able to walk to the back of the frame for pantographs.
I got it 18 months ago with an interest free loan which I have half paid off already. In that 18 months I have done 26 quilts on it plus several practice quilts with muslin. The learning has been fun. I am now doing a couple of quilts for friends. I don't think I want to start a business - that would spoil the fun.
Baby Lock had a 4 day class in St. Louis which was absolutely superb. I was really ready to go after that. It was included in the deal at the quilt show although I had to get to St. Louis and stay in a hotel for 4 days. Baby Lock hooked me up with a roommate which helped alot with the cost.
I agree that the dealer and classes are very important. Also trying out the set-up on several different brands.